Tried to jump start...burning smell...

[HardInThePaint]

Yeah that is strange. And it really is annoying that u have no idea what caused that. Whats also a problem is that now u are probably going to be very hesitant to try to jump your car again (that is until u figure out what the hell happened). Hopefully u don't ever leave your lights on anymore!

[Chronuss]

I just did a quick search. The car that our friend has is a 2004 Camry...it has an electronic ignition. This may be what cause my board to fry.

[batever]

I don't know specifically why the TCU would be subject to that kind of electrical burnout. But if you suspect the jumpstart procedure, one thing you can do in the future is make sure the "donor" car is already started before you hook up the cables to your car. (or complete the circuit) That way the donor car has time to stabilize voltage before sending it to your car.

Now, the burning out on the board is a little weird because mere voltage spikes shouldn't cause that. it's the amount of current going through that part of the board that causes burnout. I don't see how a minor voltage spike could cause that level of physical overload (total current overload) to blacken the board.( I do see one way it could theoretically do so, having to do with the distance between leads on the board and the voltage involved creating a temporary plasma connection between two normally unrelated leads (plasma has extremely low electrical resistance so would draw excessive current into the components in that case)--but again, this is just me speculating.) [When you see a spark when connecting an electrical circuit, you are seeing air that has been transformed into the plasma state, whichh occurs when the voltage in partial/broken circuit exceeds the spark air gap between the current-carrying and ground leads in question--the current is jumping through the air and transforming it into plasma, and completing the circuit at the same time.]

More likely scenario: One thing that could cause current overload in an electronic subcircuit on the board is a failed (weakened, then overloaded) capacitor in the board or a failed resistor upstream of the area that burned. The capacitors and resistors are placed to moderate/control the amount of current flowing through the subcircuit, tytpically to protect components such as diodes or transistors, which are very a current sensitive. After they fail, the subcircuit would draw excess current for the wiring there and overheat either the wiring or the components themselves. Hence the burning. The charging voltage could have been the straw that broke the camel's back here.


No expert on the TCU or even the car's electrical system here, I'm just offering my suspicions and thoughts.

If you REALLY want to protect your car's electronics when jumping your car, disconnect your negative battery clamp and run the cables between your positive and negative battery poles to the donor car's positive battery pole and his engine block. This will give a very fast (some would say excessively fast) charge to your battery, at risk of building up gas pressure within the batter. So do this for maybe 5 minutes tops and stay some distance from the recharging battery, preferably out of line of sight or at least with your back to it.

Then, after you have disconnected the other car from the circuit, with the ignition in the off position, reconnect the negative battery clamp on your car. It will now be safe (from the inside of your car) to complete the circuit at the ignition without danger of sparking a hydrogen explosion at the battery.

[batever]

Okay, so I'm an idiot and left my headlights on all night. Friend came over and we tried to jump start the CB.

if you don't have a battery charger, you can rig up a cheap (pretty much free) and rudimentary home trickle charger by taking a simple DC transformer (like for an old piece of electronics equipment that you don't use anymore) and running the negative DC output lead to the negative of the battery and the positive to the positive with alligator clips.
(Run it direct to your battery after undoing the negative clamp on the battery to isolate the circuit from your car.) Then , after your connections are made, plug the transformer into an extension cord and the extension cord into a distant wall circuit.

Anything that puts out 12V and 1 amp or 2 amps (1000-2000milliamps) or so would be adequate.


Then wait about an hour or two ( putting between one and two, or between two and four, extra amps into the battery) and give the car a try. If it doesn't work, give it another couple of hours. Watch the battery for bulging. (won't happen with this charge rate, but still).


Always disconnect the charging circuit at the farthest point possible from the car, and preferably with your back turned to the battery.

[Chronuss]

All I can say, old battery to Wall-Mart + 3 year replacement = new battery for me.

[1990cb7tn]

ive never heard of that doing that before like that and i have given and had jumps alot in the past and nothing has ever happend to me like that. i have had the cables frie and melt but never something on my car bun like that. the closest i have ever come to that is the hot cable burnedadn ruined my starter before but thats because something was touching metal (stupid me) but glad to hear your gettting her back on the road i sure would be scared to give and recive jumps anymore.. best of luck

[Chronuss]

Got my $55 eBay TCU. Hooked it up before bolting anything down and was off and runnin'. Ran it around the block to make sure it would shift properly and the Sports light would come on and off. Twenty minutes later, the plate was bolted back down and carpet back in place.